Engine Trade Deal Part 2 (OS 91 FX & Enya 60 Model 7032) 

FX series the legendary line of reliable easy to break in and most user friendly 2 stroke engines made by OS, maybe cyl liner not very long lasting because of nickel plating is not as hard as chrome plated ones but parts were relatively cheap and readily available. Still missing Bella.

The 91 hasnt been run I would say maybe the owner put s tiny bit of oil to store it? the OS 91 is a beast of an engine easily matches the 120 $strokes IMHO

Both engines are fantastic David.. Os and Enya are both I would say at a very similar level on quality..Like the chrome plate carter!!!

Just found a deal on the later version of the 91 FX, NIB with a new pitts muffler and mount included as well for under $200 usd. He also had 2 more that are nib but without the extra muffler and mount.

My thought is it hasn’t been run. The receipt said 2003. So what 16 years? I think the oil, had it been after run or fuel lube residue would have had the distinctive smell of one or the other and the viscosity would have broken down to more of a thick oil. That seemed pretty thin, similar to assembly oil, just old and subjected to temperature and humidity changes. It was definitely not hermetically sealed. Now if you want what a never run engine looks like loaded with assembly oil, you should see my Dub Jett .72 control line engine. I’m afraid to fire it up! It’s a piece of art. Want to put it on your bench?

Looks good to me, possible as you say that tooling oil could discolor over time. 1966 was a good year for you? (You don’t look much older than me if at all) I was only 2 years old then. That’s the year my dog Sammy (dachshund) bit me in the arm when I tried to take his food dish away lol. Not so good of a year for me. Congrats on the cool engine swaps.

My Saito 125 lost compression. One valve is not moving when crank shaft is rotated. Where can I send it for repair?

looking forward to see the 91 run. gonna compare the performance to my 90fsr after yours is broken in

I forgot, with the later HS valve mount The 91 had excellent transition.

I have 2 os 40's i bought in the late 80's nib never ran yet and the oil is still clear and not that much

my very first engine was an enya40tv, learnt to fly with it never let me down i wish i still had it

I recently purchased an fx 91. Upon researching the engine due to no paperwork, I found that it came in two versions. The early one had the remote HS needle mount cast into the backplate like yours. According to the info that I found, after the engine warmed up, midrange performance fell off due to the heat transfer from block to HS assembly causing a semi vapor lock condition. I will be curious to see you run the 91 and see if the condition manifests. The engine that I bought was the later version with the HS valve on a standard metal bracket. I put on a 15x8 APC on mine on the stand and got a max of 13,420 rpm with a smooth idle at 2150 to 2250. Sweet engine!

Almost looks like after-run oil. I've seen after-run oils that were reddish in color.

Don't they run them at the factory?